Charles e



(No Model.)

0. E. BALL.

, DIGESTEB FOR PAPER PULP.

No. 336.078. Patented Feb. 16, 1886.

.- UNlTED Scares CHARLES E. BALL, or NEW YoR-Kfx. Y.

DIGESTER FOR PAPER-PULP.

SPECIFICATION forming part of Letters Patent No 336,078, dated February 16, 1886.

kpplicationflledhiayli,1885. Serial No. 165,465. (No model.)

To all whont it may concern:

Be it known-that I, CHARLEs-E BALL, a citizen of the United States, and a resident'of New York, in the county and'State of New" employed iuthe digesting process, and as such process is carried on under considerable steampressure, it is the usual custom to construct these boilers or digesters of iron and to line them with lead. This lead lining has been applied to the boilers and affixed-thereinin various ways, none of which, however, has

proved entirelysatisfactory. 'The sudden changes of temperature to which. these boilers are subjected during the digesting process and the difl'erence in expansion and contraction betweenthe iron casing and the lead lining have the client of causing the lead to warp and cu rl-up at various points, while it is strained and spread at other points, and eventually the lining becomes cracked or broken, and the liquid or vaporous acid in the interior, escaping through the fissures in the lead, attacks the iron casing. The usual manner of detecting the leakage of any acid through the lead lining is by scenting the sulphureted hydrogen whichmayescape at some of the joints of the iron casing. The life of these boilers of digesters is usually not more than two or three weeks, the replacement of the lead lining being then necessary.

My invention has for its object the provis ion for preventing as far as possible any distortion, warping, or breaking and consequent leakage of the lead lining in boilers or digesters used in the manufacture of paperpulp.

-My invention. hasi'orits further object the provision of means for immediately indicating by a s'onorous signal the escape of any acid "through the lead lining,whether such acid be in a liquid'or vaporousform.

' My invention consists, first, in constructing the boiler or digester in such manner as to "leave a space between-the lead lining and the iron casing, and maintaining an equal pressure on both sides of the lead lining while the boiler or digester is in operation; secondly,in the provision of an electric signal adapted to be automatically operated upon the escape of any bfithe acid contents of the boilerthrough the leadlining.

Referring to the accompanying drawings, wherein Figure 1 is a vertical central section of a vertical stationary boiler embodying my improvement, and Fig. 2 a detail Adesignates the exterior iron casing of the boiler, which is of the usual form and construction, and need not therefore be particularly described. Bdesignatestheleadlining. This lead lining is separated from the interior of the iron casing A by a space, 0, and maintained at that distance by means either of rings of lead D, which are formed integral with the lining B or -attached thereto in any suitable manner, or by means of rings of iron E, which are formed integral with or attached to the casing A.

In Fig. 2 I have shown a means for securing the iron casing and lead lining together, and at the same time sustaining the rings D or E in position, such means consisting of bolts F, passing through the casing, the lining, and the rings, The rings D or E, whichever may be employed, can be made continuous all around the lining, in which case they should be-provided with holes ,for the passage of steam or water; or they may be replaced by a number of lugs or projections arranged at proper intervals.

It is my design to maintain constantly an equal pressure upon the outside and inside of the lead casing, and in order to do so I attach a branch pipe to the steam-pipe which conveys steam to the interior of the boi ler,which branch pipe I lead into the space 0, between the lead lining B and the casing A. This space may be kept full of steam alone, the pressure being the same as that upon the inside of the lead lining, or a quantity of water should be provided for the ingress and the egress of the solutions used,-and the boiler is of course provided with the usual means for. introducing and discharging the'material to be acted upon in the boiler; .At or near the bottom of the boiler are fixed twofw'ires,1 I, which pass through the-exterior casing, A; and are insulated therefrom. The inner ends of these wires are brought close together withoutcontact, and their outer ends areconnected to the terminals of an electric circuit i'nwhicliare included a battery, K,and anzelectrie sig.' naling apparatus, L. W f i Operation: The apparatus being constructenters the interior of the boiler and alsbthls space'Q, An equilibrium offpressure is there.- uponestablished between theinterior and ex-- teriorflsurfaces of the lead Iiningwhicbis v maintained during the time the conjtents of the boiler are under pressure. The lead lining and theiron casing'of course expand and contract as the temperature increases or diminishes; but being separated from one-another Witnesses; occur, the wate'rzof condensatlon, into vvwhich the wires I I project, becomes acidulatj'ed" and 1:

" Havingdescribed myinvention, I- claini- Ina boiler for digesting materials by the 40 aetionkof acids, the combination, with an exterior casing and an'interior lining separated x from said casing by a'space', ofsteam-pipes leadinginto the interior of the boiler and into the space between the lining and the casing, 4 whereby an equable steam-pressure may be maintained oneach side of said lining, sub-Q 'stantiallyas described. ed and arranged as described,'.the material to be digested and the desired acid solution introduced into the boiler,.steam is turned 0n and 2; -.In' a boiler for digesting by the action of an acid solution or vapor, the combination, 5o with an exterior casing and alining separated from said casing by a space, of anelectric signaling'apparatus whose circuit-terminals project into saidspac'e, substantially as described.

3. Ina boiler'for 'di-gestingvmaterials by the 55 'action'of acids, thecombination, with the ex-' terior casing and an interior lining, of an electric-signaling apparatus adapted to beautomatically operated upon the escape of acid through the lining, substantially as set forth. 6o In testimony that I claim the foregoing as my invention [have signed my name, in pres "-ence of.t wo witnesses, this 9th dayof May,

- CHAS. E, BALL.

GEORGE EsoHBA o I, GEoRcE THoRNe. 

